[PROJECT] Online clock tanpa RTC dengan Arduino & Ethernet Shield

Kita terkadang punya project yang sudah terhubung dengan Ethernet dan Internet. Kita juga sering membutuhkan data logger sehingga waktu yang akurat dibutuhkan. Banyak orang yang menambah modul RTC. Penambahan modul RTC ini sudah benar menurut fungsinya. Tapi terkadang kita juga malas karena boardnya jadi lebih kompleks. Padahal kita bisa mengambil data waktu di NTP, yang berformat UNIX time.
Apa itu NTP Server Beserta Fungsinya ?
NTP Server - NTP merupakan kepanjangan dari Network Time Protocol adalah sebuah protokol yang berfungsi untuk menyamakan waktu dari setiap komputer yang terhubung dengan jaringan dengan komputer server dalam jaringan tersebut, bisa pada jaringan LAN (Local Area Network) maupun pada jaringan Internet, NTP itu sendiri menggunakan jalur data TCP/IP. NTP Menggunakan komunikasi UDP dengan port 123.

Library yang dibutuhkan :

1. Ethernet (bawaan Arduino)
2. TimeLib (https://github.com/PaulStoffregen/Time)

Copy paste program dibawah ini ke Arduino IDE. Asal library benar pasti akan sukses. Pastikan bahwa koneksi internet nya benar (Gateway, DNS, Subnet, dsb..).

Coding:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129

#include <SPI.h> #include <Ethernet.h> #include <EthernetUdp.h> #include <TimeLib.h> // Enter a MAC address for your controller below. // Newer Ethernet shields have a MAC address printed on a sticker on the shield byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0x12 }; // Set the static IP address to use if the DHCP fails to assign IPAddress ip(192, 168, 5, 198); IPAddress myDns(140, 0, 223, 250); IPAddress gateway(192, 168, 5, 9); IPAddress subnet(255, 255, 255, 0); unsigned int localPort = 8888; // local port to listen for UDP packets unsigned long unixTime, ticker1, ticker2, ticker3, minus; //char timeServer[] = "ntp.lipi.go.id"; // time.nist.gov NTP server char timeServer[] = "pool.ntp.org"; // time.nist.gov NTP server char timeZone = 7, ite = 0; const int NTP_PACKET_SIZE = 48; // NTP time stamp is in the first 48 bytes of the message byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets bool DHCP = true, reqTime = false; // A UDP instance to let us send and receive packets over UDP EthernetUDP Udp; void setup() { // Open serial communications and wait for port to open: Serial.begin(115200); while (!Serial) { ; // wait for serial port to connect. Needed for native USB port only } // start the Ethernet connection: //if (Ethernet.begin(mac) == 0) { Serial.println("Failed to configure Ethernet using DHCP"); Ethernet.begin(mac, ip, myDns, gateway, subnet); DHCP = false; } setSyncProvider(getNtpTime); Udp.begin(localPort); ticker2 -= 60000; } void loop() { if (millis() - ticker2 >= 60000) { ticker2 = millis(); ticker3 = millis(); sendNTPpacket(timeServer); // send an NTP packet to a time server minus = (millis() - ticker3) / 1000; reqTime = true; ite = 0; } if (millis() - ticker3 >= 1000 && reqTime == true) { ticker3 = millis(); ite++; if (Udp.parsePacket()) { Udp.read(packetBuffer, NTP_PACKET_SIZE); unsigned long highWord = word(packetBuffer[40], packetBuffer[41]); unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]); unsigned long secsSince1900 = highWord << 16 | lowWord; if (secsSince1900 != 1145324612) { unsigned long epoch = secsSince1900 - 2208988800UL; unixTime = epoch; setTime(epoch + timeZone * SECS_PER_HOUR + ite); reqTime = false; } } } if (millis() - ticker1 >= 1000) { ticker1 = millis(); digitalClockDisplay(); } if (DHCP == true) Ethernet.maintain(); delay(10); } // send an NTP request to the time server at the given address void sendNTPpacket(char* address) { // set all bytes in the buffer to 0 memset(packetBuffer, 0, NTP_PACKET_SIZE); // Initialize values needed to form NTP request // (see URL above for details on the packets) packetBuffer[0] = 0b11100011; // LI, Version, Mode packetBuffer[1] = 0; // Stratum, or type of clock packetBuffer[2] = 10; // Polling Interval packetBuffer[3] = 0xEC; // Peer Clock Precision // 8 bytes of zero for Root Delay & Root Dispersion packetBuffer[12] = 49; packetBuffer[13] = 0x4E; packetBuffer[14] = 49; packetBuffer[15] = 52; // all NTP fields have been given values, now // you can send a packet requesting a timestamp: Udp.beginPacket(address, 123); //NTP requests are to port 123 Udp.write(packetBuffer, NTP_PACKET_SIZE); Udp.endPacket(); } void digitalClockDisplay() { // digital clock display of the time Serial.print(hour()); printDigits(minute()); printDigits(second()); Serial.print(" "); Serial.print(day()); Serial.print(" "); Serial.print(month()); Serial.print(" "); Serial.print(year()); Serial.println(); } void printDigits(int digits) { // utility for digital clock display: prints preceding colon and leading 0 Serial.print(":"); if (digits < 10) Serial.print('0'); Serial.print(digits); } time_t getNtpTime() { return unixTime + timeZone * SECS_PER_HOUR; }